A cookie is a small piece of information stored on your computer by a website you visit.
Cookies often store your settings for a website, such as your preferred language or location. This allows the site to remember who you are and how you like to look at things.
Cookies are able to store a wide range of information, including personally identifiable information (such as your name and e-mail address). However, this information can only be stored if you provide it – websites cannot gain access to information you didn’t provide to them, and they can’t access other files on your computer.
For more information on cookies, see All About Cookies.
All browsers allow you to turn off cookies if you wish. This may make certain features stop working on websites you visit, and it may make browsing less smooth in general.
You will have to look at the settings for your specific browser in order to control how it handles cookies.